GCE

References: Chai2024

Enables grand canonical SCF calculations for slab models with a target work function specified by the user. The current implementation is intended for three dimensional periodic calculations and should be used together with the planar counter charge model. The planar counter charge screens the net charge of the DFT slab, so that the work function can be obtained from the planar averaged Hartree potential in the implicit solvent region or vacuum region. During the SCF iterations, the work function is mixed toward the target value. The reported GCE charges during SCF iterations are the current net charge of the DFT system excluding the planar counter charge. A positive value means electron deficiency. The input CHARGE value in the DFT section defines the reference charge state. The quantity N_e^(abs,alpha) is evaluated as the input CHARGE value minus the reported GCE charge. The reported GCE free energy is the sum of the DFT total energy and the product of the target work function and N_e^(abs,alpha). [Edit on GitHub]

Keywords

• SECTION_PARAMETERS

• MIXING_COEF

• TARGET_WORKFUNCTION

Keyword descriptions

SECTION_PARAMETERS: logical = F

Lone keyword: T

Usage: &GCE ON

Controls the activation of grand canonical SCF [Edit on GitHub]

MIXING_COEF: real = 3.00000000E-001

Usage: MIXING_COEF 0.3

The proportion of the target work function mixed with the work function of the previous SCF iteration [Edit on GitHub]

TARGET_WORKFUNCTION: real = 1.60000000E-001 [hartree]

Usage: TARGET_WORKFUNCTION [eV] 0.16

The user input target work function of the symmetric slab model [Edit on GitHub]